1470MPa级双相钢的性能特征与强韧化机制  

Mechanical Properties and Strengthen-toughening Mechanism of 1470 MPa Grade Dual-phase Steel

作　　者：赵征志[1,2] 佟婷婷[1,2] 赵爱民[1,2] 苏岚[1,2] 张岩[1,2] 

机构地区：[1]北京科技大学冶金工程研究院,北京100083 [2]现代交通先进金属材料与加工技术北京实验室,北京100083

出　　处：《材料研究学报》2014年第11期828-834,共7页Chinese Journal of Materials Research

基　　金：国家自然科学基金51271035项目资助~~

摘　　要：对0.16C-1.38Si-3.2Mn双相钢进行轧制和退火处理,用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、电子背散射衍射(EBSD)等手段表征试验钢的微观组织和断口形貌,分析试验钢经退火后钢板的力学性能和加工硬化行为,重点研究了试验钢晶粒细化的强韧化机制。结果表明:试验钢在800℃退火后的显微组织主要由8.8%铁素体和91.2%回火马氏体构成。退火后的钢板具有良好的综合力学性能,屈服强度为873 MPa,表现为连续屈服特征,抗拉强度为1483 MPa,总伸长率为11%,屈强比为0.58;试验钢的Mn含量、退火前的初始组织、冷轧大变形以及退火过程中关键工艺参数等都有利于试验钢退火板的晶粒细化,铁素体尺寸为1-2μm,马氏体板条束的有效晶粒尺寸为0.2-1.5μm。细小的晶粒有利于阻碍位错的运动和增加裂纹扩展的阻力,从而提高了钢板的强度和塑韧性。Plates of 1.5 mm in thickness of a model dual-phase steel 0.16C-1.38Si-3.2Mn was prepared by complex processes of rolling and annealing.The mechanical property and work hardening behavior of the steel after annealing were examined.The microstructure and fracture morphology of the steel were characterized by scanning electronic microscopy(SEM),transmission electron microscopy(TEM) and electron backscattered diffraction(EBSD) techniques with emphasis on the strengthen-toughening mechanism of grain refinement of the steel.The results show that the microstructure of the steel annealed at 800℃ consists of ferrite(8.8%) and tempered martensite(91.2%).The annealed steel exhibits good comprehensive performance:the yield strength of 873 MPa with characteristics of continuous yield,tensile strength of 1483 MPa,total elongation of 11% and yield ratio of 0.58.The factors such as the manganese content of the steel,the initial microstructure before annealing,the large deformation of cold rolling and the key parameters of annealing process are all conductive to the grain refining of the steel,as a result the size of ferrite phases is about 1- 2 μm and the effective size of martensite bundles is0.2-1.5 μm.The refined grains may play an important role in blocking the movement of dislocation and increase the resistance to crack propagation thereby enhance the strength,toughness and ductility of the steel sheet.

关 键 词：金属材料 超高强双相钢 细晶 强韧化机制 加工硬化行为 

分 类 号：TG142.1[一般工业技术—材料科学与工程]